Users may not create topics, posts, or private messages containing or relating to the following material (especially pertaining to Motorola copyrighted software, unless you want Motorola to come along and shut this site down):

This forum is dedicated to discussions pertaining specifically to the Motorola ASTRO line of radios (those that use VSELP/IMBE/AMBE), including using digital modulation, digital programming, FlashPort upgrades, etc. If you have general questions please use the General or Programming forums.

The TX audio must be routed to the new point of entry, otherwise, it gets filtered and 4 level FSK won't pass.

RICK's point of entry was filtered, and the RICK has adjustments not needed. Alhtough I suppose you could use a RICK as transparent enable / disable as long as the audio doesn't get routed thru it. Only the call alert I/O.

Cool. Thanks for being the one to finally put it in a form that can be seen.

I just built a portable repeater from two king LPH handhelds. I would like to make it pass securenet but I'm struggling with the same issue of how to select the proper audio path.

Short of using some sort of pl decoder that senses analog and a specific tone to switch in the analog audio path I can't figure out what to do. I would like to make it automatically sense what type of modulation is going through it but I guess that's not going to happen.

While this not usefull for Astro, or at least I havn't tried it yet, using MX-S or crystal version portables work great for Securenet. You will need either a Secure MX portable as a reciever or a Securenet box from a Syntor or SyntorX to get the reclocked digital signal, then merely rerout to the PL input of the radio.

Would this be possible with Astro Spectras? I have a need for this on commercial service and if I can use Astro Spectras to require the correct digital code to key up the opposite transmitter, it owuld be perfect!! (it would actually be two back to back radios...one talking to a Quantar, the other talking to mobiles in a rough area that cannot talk directly to the main rptr). I could use the BUSY light off the head to key the opposite transmitter..of course I will need 4 radios to do this full duplex in both directions (but I have plenty of spares!! HMM time to hit the bench with this idea..

I have done thie with the Icom 1821D radios and 2721D radios. They work like a champ. Just put fans on the TX radio. I have 3 portable systems in use to date with many more to come, However only one NAC ,and TG can be used.

I found a program over at Radio Reference named the Knack. It decodes NAC codes. I haven’t tried the Knack, but I was wondering if it would be possible for someone to write a program similar to the Knack to decode the NAC of a receiving radio and use it for a COR input to a controller? It seems if it can decode and display the NAC ID, with a few mods to the code it could be changed to allow serial port control for a specific NAC. If that would be possible this would solve the problem of running a wide open transparent repeater for IMBE. You could write the software to allow only specifics NACs to give you a low or high on one of the serial port pins. You could use this signal similar to a digital COR signal line. If the proper NAC is present it would allow a repeater to key, if not it will not key up on noise or skip.

This could be run a cheap laptop or PC. Since there are thousands of low end machines laying around.

Ive been trying to use a GM300 for the transmitter, GE master II reciever.
I found the COR time faster and audio was alot flatter with the GE reciever, problem I am having is the decode at the other portable. The radio (other p25 radio not repeater radios) dosent pass audio like its trying to decode and then gives up and processes it as analog noise. Help me out here guys, audio levels are below clipping and dev set at 2.3k. Got audio from vol/sql high (buffered discriminator) going to the TX flat audio pin in on the GM300. I canot see anywhere on the GM300 that has a TXA printed on it like the Maxtrac. Any ideas will help alot, works perfect with analog and DPL...just not p25. Thanks

bellersley wrote:Well now. I have a nice MSF5000 sitting here not doing anything useful. I wonder if you could use the theory and such in this "hack" to work on an MSF. Or maybe even a GR1225. That'd kick a$$.

HELP, I am ready to go here but looking for instructions to use GM300's. If anyone has any documentation or instructions on the procedure to use GM300's for this project, please forward. Thanks as always.

Kyle

In Time of Crisis, You will Not Rise to the Occasion but Rather Default to your Level of Training!

KD8CPP wrote:What i want to know is, could you have a Astro Spectra for recieve, and port the audio from it into the mic. port of another Astro Spectra, or the XTL series for that matter?

Yes you certainly could. However. The re-transmitted audio won't be as good as what you'd get from the Maxtrac pass-thru repeater. In your example, you would be "double vocoding" which will most likely lead to considerable audio quality loss. Any "artifacts", that is, packet losses and other digital "noise" would be greatly increased in the repeated audio.

If the RX signal is very strong and the decoded audio has a very low bit error rate, the re-transmitted audio won't be bad at all, but as soon as you start getting iffy RX audio, expect TX audio to go down the tubes.

But, if you have two astro radios sitting around and want to give it a try, you might find it works just fine for you.

radio-link wrote:I did a repeater with some old crystal controlled radios, doing FM, APCO25 and 12kbit securenet just fine. The old stuff sometimes is much easier to adopt to those new modes

OK, now I have set up a repeater with two GM1200 (european MTP1327/1343-trunking radios in conventional mode, Renaissance-series M01RFL9CK4AN), and D-Star passes quite good through it! Unfortunately I still can not program the Astro Sabers due to "codeplug to new" to the repeaters frequency, so I could not test if it works for P25, but I guess it will do.

The repeater is described at http://www.db0fue.de, but up to now only in german. Maybe I will find to translate the site into english druing the next one or two weeks, at least the technical details.

What I did is simply program both radios with "data channels", connect CSQ to PTT and demodulator out to modulator in. That was it

radio-link wrote:... so I could not test if it works for P25, but I guess it will do.

Update: D-Star and P25 work just fine; also in a cross band repeater setup with four radios (2*146 MHz, 2*440 MHz) it works great and is able to connect both bands together, FM, D-Star, P25, whatever you want to use. The "live" repeater however still is 440 MHz only, I do not have a frequency assignment for 146 MHz for it - so it was just a test on the workbench.

Seems like this post is slightly ancient, however if I could revive it with your help...

1. For whatever reason after downloading the application (maxtrac how to file) to open the file, it won't open. Any suggestions?

2. To be able to coordinate a pair on VHF, we will have to have a NFM 12.5k spacing machine, is this Maxtrac and/or MSF modification plan a NFM or standard 25k deviation repeater?

3. Has anyone been able to enable a NAC computer controlled decode COR signal by using Knack or similar PC programs? Something that will see the NAC, enable the serial port, a box to convert the serial info to a high/low pulldown for a simple controller?

I got the visio reader to work, so here is a new very important question...

- Will this work with two VHF GM300s (Maxtracs)?

- Hard to tell by this schematic if when in non-PL "APCO" transparent mode, does the transmitter stay keyed all the time or does it only engage on a COR signal? I didn't see any sort of a "controller" in there for this logic.

I hope it would work on VHF and be capable of NFM? If I am correct, isn't ASTRO mode done in NFM mode by the user radios automatically anyway?

W1HVN wrote:I got the visio reader to work, so here is a new very important question...

- Will this work with two VHF GM300s (Maxtracs)?

- Hard to tell by this schematic if when in non-PL "APCO" transparent mode, does the transmitter stay keyed all the time or does it only engage on a COR signal? I didn't see any sort of a "controller" in there for this logic.

I hope it would work on VHF and be capable of NFM? If I am correct, isn't ASTRO mode done in NFM mode by the user radios automatically anyway?

Thanks!

I did not use this schematic, but with my GM900/GM1200 setup I used the carrier squelch to key the transmitter. Of course it would be possible to find other solutions, but for me it works just fine this way. It allows usage of FM, P25 and D-Star on one repeater.

I have mine setup with two maxtracs and a TP-3200 tone panel running in carrier squelch mode. I was able to retain the use of the controller features such as hang time and CW ID by modding the controller with a small reed relay. What happens is that the LED in the panel that signals the presence of a carrier runs the small relay. When the relay closes it basically eliminates all the signalling features of the panel and makes a straight audio path through it. That keeps things clean for the use of P25 or DStar. When the LED goes dark the audio path is reconnected and the CW ID is played normally. It makes for a nice silent hang time as well. An end of transmission tone is sent by the transmit radio which is programmed with a short two digit DTMF Id set to post transmission. The setup is placed in a 19" rack and connected to a Milcom 160 watt amp that feeds a set of Wacom duplexers.

Ok, we are in the process of putting together a cple GM300s on VHF. Here is our question, same question that was asked back in 2006, with no response. Maybe someone has done this mod with a pair of GM300s. If anyone has done this, please send a reply.

Here was the question back in 2006

Phoneman wrote:"Help me out here guys, audio levels are below clipping and dev set at 2.3k. Got audio from vol/sql high (buffered discriminator) going to the TX flat audio pin in on the GM300. I canot see anywhere on the GM300 that has a TXA printed on it like the Maxtrac. Any ideas will help alot, works perfect with analog and DPL...just not p25. Thanks"

We have the TX GM300 open, no TXA on the board as the Maxtrac has. Where do we insert audio bypassing any filtering on this radio?

Does pin 5 "TX Flat Audio" accomplish this? Was his problem due to incorrect point where audio was inserted or something else?

We have an older Micor for UHF as well, and in theory it should work as long as you can find the points on the rx and exciter to bypass filetering. One word of caution, do some experimenting and see if by bypassing such filtering if you also bypass any limiting as well, if so you may exceed your 5k dev limit in analog. P25 is reported to be 3.5k dev in wide fm with the GM300s.

The repeater in CT has been up and running and has done an exceptional job.

Sorry, perhaps it's a bit misleading. The repeater is "open" in CSQ. All of our users use a NAC of 073 or PL 77.0 on the system, however in actuality, any can be used, these are our set standards. The end user unit encodes, decodes and is the "gatekeeper" of what comes through the speaker, the repeater just spits out what it hears. If using analog and a PL, you get a "gated squelch" type product, which is nice. Until someone springs for the Quantar, this is it folks! I'm just a partial owner, another amateur operates the repeater. He is trely the brains and capability behind the repeater.

KE7JFF wrote:I recently got access to a bunch of Micors and I wonder if I can use the same principal on them for this.

Anyone ever try this wtih Micors out of curiousity?

I have not tried this particular application with Micors, but either a base or mobile UHF Micor would be suitable as they use direct FM of the crystal for modulation. The mobile actually modulates the 11.7 or 16.7 MHz offset oscillator while the base station modulates the channel element. In both cases you would want to bypass the square blue chip that provides audio shaping and limiting. The analog audio when fed this way is schweeeet!

The VHF base station Micor exciter is also direct FM, while the mobile VHF Micor used phase modulation and would not be suitable to this application.

I don't know what waveform shaping is inherent in the recovered signal from the buffered discriminator, but feeding the audio to the exciter this way could certainly splatter so watch your deviation carefully. Others can advise on the proper setting for best performance of both analog voice and digital modes.

***I have mistakenly programmed a CDM1550 to use the pin 5 "flat audio" input for a generic, run-of-the-mill remote application and regret it. The audio is not filtered nor limited, so while it would be good for this application, it stinks for plain LMR voice because I can't get sufficient punch out of the audio without it splattering.

So pin 5 flat audio for data and transparent audio into the transmitter,

pin 2 for regular old fashioned limited mic audio in.

Last edited by boteman on Fri Apr 17, 2009 12:34 pm, edited 2 times in total.